The present disclosure is related to patient support apparatuses that include inflatable support structures. More specifically, the present disclosure is related to patient support apparatuses including control structures for controlling the rate of inflation of an inflatable support structure.
Patient support apparatuses such as beds, and more particularly hospital beds, are known to include one or more inflatable support structure(s) for supporting at least a portion of patient on the inflatable structure. The pressure in the inflatable structure may be varied to change the interface pressure exerted on the skin of the patient supported on the inflatable structure. In some cases, the volume of an inflatable structure is substantial, even while the operating pressures are relatively low. The source of pressurized air used to inflate the support structure may have a sufficient rate of displacement to fill the volume of the structure in only a few minutes. Once filled, the volume of air required to maintain the inflatable structure at the appropriate pressure is significantly lower than that required to initially inflate the structure.
The competing requirements of low flow during normal operating conditions and high flow for the initial fill of the inflatable structure presents a trade-off. A high flow pressurized air source provides for a timely initial fill but has excess capacity during the low fill operation. A low flow pressurized air source on the other hand, may fail to provide sufficient flow to provide a timely initial fill. Furthermore, conventional high flow pressurized air sources are often noisier and cause more unwanted vibrations than low flow pressurized air sources.